This document summarizes estimates of change in mature individuals over time for Pacific salmon Designatable Units (DUs) and associated probable COSEWIC status designations. These estimates can then be used to help COSEWIC’s Marine Fishes sub-committee identify high priority DUs for formally assessment. Data sources are detailed here and all code to reproduce the analyses in this document is here. These materials are solely intended to support the Marine Fishes sub-committee of COSEWIC, and may not be appropriate for other applications.
Initial thoughts on potential decision nodes in the prioritization process.
Have DUs been formally defined by COSEWIC? Chinook, sockeye, and coho salmon DUs have been defined (reports available here), formal pink and chum DU identification is in progress. If yes then proceed.
Is information on mature individuals over time available at the DU scale? If yes then proceed.
Has DU been previously assessed by COSEWIC? If yes then consider a re-assessment, otherwise proceed except for DUs that have already been approved for a status assessment.
What is the DUs probable designation based on percentage change in mature individuals over past three generations? If special concern, threatened or endangered then proceed.
Are there spatial considerations? Are there commonalities in threats, designations, and/or data landscape at a regional scale that suggest a group of DUs should be bundled together?
Figure 1. Status of all DUs. For DUs that have been previously assessed by COSEWIC the official status is shown, otherwise probable status is inferred based on percent change in mature individual abundance over the most recent three generations of data.
Figure 2. Probable status of unassessed, but formally defined, Pacific salmon DUs (excluding those previously assessed by COSEWIC or recommended for status assessment) based on rate of change in mature individuals over most recent three generations.
Plots of reconstructed number of mature individuals (spawners) over time for each DU, by region and species. Show are both raw and log(e) transformed estimates, and for the later the trend over the most recent three generations (red line) or entire time-series (black dashed line) are also shown.